The present invention relates to the perfume industry. More particularly, it is concerned with new cyclic compounds capable of releasing fragrant alcohols.
The perfume industry is displaying a particular interest in compounds which are able to prolong a fragrancing effect for a period of time, in particular to mitigate the problems encountered when using volatile perfuming ingredients. Compounds are known which, only under certain conditions of activation such as light, heat, or the presence of enzymes, notably lipases, are capable of releasing a fragrant substance over an extended time period. For example, international patent application WO 95/04809, which belongs to the present applicant, discloses a process for perfuming fabrics washed in the presence of a lipase-containing detergent comprising a compound of formula 
The lipase constitutes an activating agent which is necessary to provide the release of a perfuming molecule from the cited compound. These compounds may be used in various applications. The washing of textiles in particular is a field in which scientists are always searching for new means enabling the effect of perfuming substances to be perceived for a period of time after the washing and drying operations. This because many substances which have odours especially suitable for this type of application are known not to be long-lasting on washed items, with the result that their perfuming effect is perceived only briefly. Given the importance of this type of application in the perfume industry, research activity is on-going within this sector, notably with the aim of finding ever more effective solutions to solve the problems mentioned above.
We have now surprisingly discovered the existence of new cyclic compounds that are capable of releasing fragrant alcohols over a long period of time under totally unforeseen and advantageous conditions, that is to say, without any external assistance or activation condition. Thus, contrary to what is known in the prior art, the process of release of a fragrant alcohol by the compounds of the invention does not necessitate the presence of an external catalyst in the reaction medium, for example an enzyme and in particular a lipase. In a textiles-washing application when they are incorporated in a detergent and/or a fabric softener of any kind, these compounds thus enable the characteristic odour of the alcohol to be imparted to the textile and also enable the diffusion effect of this odour to be prolonged so that it develops over a period of time.
The compounds of the invention comply with the following formula, 
in which the dotted lines indicate the position of single or double bonds, R1 represents a radical belonging to a fragrant alcohol of the formula R1OH, X represents a nucleophilic group selected from the group consisting of xe2x80x94OH, xe2x95x90O, xe2x80x94NH2 or xe2x80x94NHR3, R3 representing a C1 to C6 straight-chain or branched hydrocarbon radical, saturated or unsaturated, or an aliphatic or aromatic ring having 5 or 6 carbon atoms, m and n define whole numbers within the range 0 to 2 such that the sum m+n is equal to 1 or 2, p defines a whole number with a value of 0 or 1, each of the symbols R2, R4, R5, R6, R7, taken independently, represents a hydrogen atom, a C1 to C4 straight-chain or branched hydrocarbon radical, saturated or unsaturated, optionally substituted and, taken two by two, they can form aromatic or aliphatic monocyclic, bicyclic or tricyclic substances with the carbon atoms to which they are bound.
Of the compounds of formula (I), menthyl-2-acetylbenzoate has been described by H. G. Rule and J. Smith in J. Chem. Soc., 1926, 553 and by L. Homer and J. Klaus in Liebigs Ann. Chem., 1979, 1232. Similarly, menthyl 2-formylbenzoate has been described by M. V. Bhatt et al. in J. Org. Chem., 1977, 42, 2697, benzyl 2-formylbenzoate has been described by N. Gautier and R. H. Dodd in Synth. Commun., 1998, 28, 3769, octyl 2-formylbenzoate by J. Barry et al., Synthesis, 1985, 40, and finally benzyl 2-acetylbenzoate by A. Kotali et al., Org. Prep. Proced. Int., 1996, 28, 622. However, these documents of the prior art contain no mention, description or suggestion of any use of these compounds in perfumery, in particular as precursors susceptible of releasing fragrant alcohols.
The compounds of the invention are capable of releasing a fragrant alcohol of the formula R1OH on hydrolysis of their ester bond. Fragrant alcohol here means an alcohol of current use in perfumery, that is to say, one which is useable as a perfuming ingredient for the preparation of perfumes or perfumed articles. The criteria to be met as a useable perfuming ingredient are known to the person skilled in the art and include, notably, a certain originality of the fragrance, stability, or even a favourable cost/effectiveness ratio. Although it is obviously impossible to provide an exhaustive list of known alcohols of the formula R1OH which may be used according to the invention, we mention by way of example anisyl alcohol, fenchyl alcohol, cinnamic alcohol, 9decen-1-ol, phenethylol, citronellol (3,7-dimethyl-6-octen-1-ol), 3-methyl-5-phenyl-1-pentanol (source: Firmenich S. A., Geneva, Switzerland), Mayol(copyright) (7p-menthan-1-ol; source: Firmenich S. A., Geneva, Switzerland), dihydromyrcenol (2,6-dimethyl-oct-7-ene-2-ol), alpha-ionol, tetrahydro-ionol, geraniol [(E)-3,7-dimethyl-2,6-octadien-1-ol], nerol (Z)-3,7-dimethyl-2-6-octadien-1-ol, (Z)-3-hexen-1-ol, 1-hexanol, 2-hexanol, 3,3,5-trimethylhexanol, 3,4,5,6,6-pentamethyl-heptan-2-ol, 5-ethyl-2-nonanol, (Z)-6-nonenol, 6,8-dimethyl-2-nonanol, 2,6-nonadien-1-ol, borneol, 1-octen-3-ol, 4-cyclohexyl-2-methyl-2-butanol (source: Firmenich S. A., Geneva, Switzerland), 6-ethyl-3-methyl-5-octen-1-ol, 3,7-dimethyl-oct-3,6-dienol, 7-methoxy-3,7-dimethyl-octan-2-ol, methyl-4-phenyl-2-butanol, 2-methyl-1-phenyl-2-propanol, 1-phenylethanol, 2-phenylethanol, 2-phenylpropanol, 3-phenylpropanol, 2-methyl-5-phenylpentanol, 2-methyl-4-phenylpentanol, 3-methyl-5-phenylpentanol, cyclomethyl-citronellol, decanol, dihydroeugenol, 8-p-methanol, 3,7-dimethyl-1-octanol, 2,6-dimethyl-2-heptanol, dodecanol, octanol, undecanol, 4-methyl-3-decen-1-ol, eugenol, Florol(copyright) (tetrahydro-2-isobutyl-4-methyl-4 (2H)-pyranol; source: Firmenich S. A., Geneva, Switzerland), 2-phenoxy-ethanol, isoeugenol, linalol, Tarragol(copyright) (2-methoxy-4-propyl-1-cyclohexanol; source: Firmenich S. A., Geneva, Switzerland), vanillin, ethyl-vanillin, anethol, famesol, cedrenol, menthol, p-menth-8-en-3-ol, 3,3,5-trimethyl-cyclohexanol, 2,4,6-trimethyl-3-cyclohexenyl-methanol, 4-(1-methylethyl) cyclohexyl-methanol, terpineol, tetrahydromugol, 3,7-dimethyl-3-octanol, Polysantol(copyright) (E)-3,3-dimethyl-5-(2xe2x80x2,2xe2x80x2,3xe2x80x2-trimethyl-3xe2x80x2-cyclopenten-1-yl)-4-penten-2-ol; source: Firmenich S. A., Geneva, Switzerland), 2,2,6-trimethyl-alpha-propyl-cyclohexane propanol, 5-(2,2,3-trimethyl-3-cyclopentyl)-3-methylpentan-2-ol, 3-methyl-5-(2,2,3-trimethylcyclopent-3-enyl)pent-4-en-2-ol, 2-ethyl-4-(2,2,3-trimethylcyclopent-3-enyl) but-2-en-1-ol, 4-(5,5,6-trimethylbicyclo[2.2.1]hept-2-yl)-cyclohexanol, 2-(2-methyl-propyl)4-hydroxy-4-methyl-tetrahydropyrane, 2-cyclohexyl propanol, 2-(1,1-dimethyl-ethyl)-4-methyl-cyclohexanol, 1-(2-tert-butyl-cyclo hexyloxy)-2-butanol, 1-(4-isopropyl-cyclohexyl)-ethanol, Limbanol(copyright) [1-(2,2,3,6-tetramethyl-cyclohex-1-yl)-3-hexanol; source: Firmenich S. A., Geneva, Switzerland), 1-heptanol, 1-nonanol and 10-undecen-1-ol. It goes without saying that this list is not complete, any alcohol capable of imparting an odour to a product to be perfumed being comprised in the alcohols of formula R1OH related to the invention.
The characteristic feature of the invention resides in the fact that the hydrolysis which induces the release of alcohol is facilitated by an auxiliary effect of the ester bond""s neighbouring nucleophilic group X. This effect provides a totally unexpected advantage, that is, it permits cleavage of the ester bond by hydrolysis under simple alkaline conditions, as shown diagrammatically below: 
Examples are the conventional conditions of textiles washing, in the course of which a change in pH occurs. The pH passes from a value corresponding to an acid medium to values corresponding to a neutral or even a basic medium during the washing cycle, thus enabling the compounds of the invention to be hydrolysed.
Otherwise the reaction is catalysed naturally in the presence of heat. This occurs for example when washing is dried, namely in a tumble-dryer. The hydrolysis reaction leads to the formation of an odoriferous substance R1OH wherein R1 has the meaning indicated above, and of a residue of the initial precursor, which is generally odourless.
The reaction requires no activation condition such as the presence of a lipase in the detergent, as reported in the prior art (WO 95/04809).
We also noticed that the preferred compounds according to the invention exhibit a common characteristic enabling them to benefit from this auxiliary effect of the neighbouring group for hydrolysis of the ester bond. The compounds claimed are in fact capable of assuming a constrained conformation in which the distance between the oxygen or nitrogen of the nucleophilic group X and the carbon of the ester function does not exceed 2.8 Angstrxc3x6m for a molecular energy calculated by the method MM2 (molecular mechanical) which differs by no more than 3 kcal/mol from the minimum total energy of the molecule.
xe2x80x9cConstrained conformationxe2x80x9d is here understood to mean a conformation different from the most stable conformation of the molecule and the achievement of which requires a specific quantity of energy relative to the minimum energy of the molecule, that is, the energy of the molecule in its most stable conformation. The respective molecular energy values are molecular parameters established for each compound with the aid of a model SGI R10000 computer using a MacroModel V6.5 programme (F. Mohamadi et al., J. Comput. Chem. 1990, 11, 440). The minimum total energies are obtained by the method known from the prior art, designated by method MM2 and by the Monte Carlo procedure executed on MacroModel. The energies of the constrained conformations are defined in accordance with the same method. We were surprised to discover that the compounds exhibiting the above-mentioned distance and energy constraints were capable of prolonged release of the fragrant alcohol R1OH over time and under the normal conditions of application, i.e. when these compounds are used in the treatment of textiles or various other surfaces.
Amongst the compounds of the invention according to formula (I) in which X represents an xe2x95x90O group, the 2-acyl-benzoates of the formula 
are appreciated.
Preferentially one may cite 3,7-dimethyl-6-octenyl 2-formylbenzoate, (E or Z)-3,7-dimethyl-2,6-octadienyl 2-formylbenzoate, 2-phenylethyl 2-formylbenzoate, (E)-3,7-dimethyl-2,6-octadienyl 2-acetylbenzoate, 3,7-dimethyl-6-octenyl 2-acetylbenzoate, and (1R, 3R, 4S)-3-menthanyl 2-acetylbenzoate. Of the preferred compounds defined above, the ones most preferred are 3,7-dimethyl-6-octenyl 2-formylbenzoate, (E)-3,7-dimethyl-2,6-octadienyl 2-formylbenzoate, phenylethyl 2-formylbenzoate and (E)3,7-dimethyl-2,6-octadienyl 2-acetylbenzoate.
On the other hand, the preferred compounds among those of the invention of formula (1) in which X defines an xe2x80x94OH group are the 2-hydroxymethylbenzoates and the esters of dihydrocoumaric acid, of the respective formulae 
One may cite in particular a preference for 3-p-menthanyl 2-hydroxy-methylbenzoate, 3,7-dimethyl-6-octenyl 2-hydroxymethylbenzoate, 2-phenyl-ethyl 2-hydroxymethylbenzoate, (Z)-3-hexenyl 2-hydroxymethylbenzoate, (E)-3,7-dimethyl-2,6-octadienyl 2-hydroxymethylbenzoate, 1-p-menthen-8-yl 2-hydroxymethylbenzoate, (1xe2x80x2R,E)-1,2,2-trimethyl-4 (2xe2x80x2,2xe2x80x2,3xe2x80x2-trimethyl-3xe2x80x2-cyclopenten-1xe2x80x2-yl)-3-butenyl 2-hydroxy-methylbenzoate, (Z)-3-hexenyl dihydrocoumarate, (E)-3,7-dimethyl-2,6-octa-dienyl dihydrocoumarate and (Z)-3-hexenyl 3-endo-hydroxymethyl-bicyclo[2.2.1]hept-5-ene-2-endo-carboxylate.
The compounds of the invention may be prepared starting from commercially available compounds and with the aid of conventional methods. Thus in a general way, starting with commercially available starting materials (acids or anhydrides) an ester bond is produced by conventional esterification of carboxyls, or by acid catalysis. Then, if necessary, the residual function (acid, aldehyde or ketone) corresponding to the future nucleophilic function is functionalised by reduction or reductive amination depending on the precursor required.
For example, the 2-acyl- and 2-formyl-benzoates are prepared on the basis of corresponding acids by simple esterification according to the following scheme: 
Other compounds such as the 2-hydroxymethylbenzoates may be prepared from the corresponding phthalates, as shown in the scheme below: 
According to another example, esters of dihydrocoumaric acid may be prepared from o-coumaric acid as follows: 
All the symbols used in the above diagrams have the meaning indicated in formula (I).
The compounds according to the invention lend themselves to any application requiring the prolonged-release effect of an odoriferous compound as defined above. They are used in particular in functional perfumery, notably in applications such as liquid or solid detergents intended for the treatment of textiles and textile softeners, for which one seeks ingredients the odours of which, once imparted to the textile during washing, can be perceived by the consumer over a period of several days thereafter. The invention enables the odoriferous effect of the above-mentioned alcohols, and thus the xe2x80x9cfreshnessxe2x80x9d of the washing, to be prolonged for several days.
The compounds of the invention may be used as perfuming ingredients for the washing in all types of detergent or softening base in which these compounds are stable. By way of example, detergents of the type of those described in the patent WO 97/34986 may be used. Moreover, as softening bases one may select those described in the patents U.S. Pat. Nos. 4,137,180, 5,236,615, or EP 799 885. Other typical compositions of detergents and softeners which may be used are described in works such as Ullmann""s Encyclopedia of Industrial Chemistry, vol. A8, pages 315448 (1987) and vol. A25, pages 747-817 (1994); E. W. Flick, Advanced Cleaning Product Formulations, Noyes Publication Park Ridge, N.J. (1989); M. S. Showell (Ed.), in Surfactant Science Series, vol. 71; Powered Detergents, Marcel Dekker, New York, N.Y. (1998); Proceedings of the 4th World Conference on Detergents: Strategies for the 21st century, A. Cahn (Ed), AOCS Presse, Champaign (1998).
Of course, the use of the compounds of the invention is not limited to the products mentioned above. These compounds lend themselves equally to all the other uses current in the perfume industry, that is to say, to the perfuming of shower or bath soaps and gels, of foam baths, of products for the treatment or hygiene of hair such as shampoos, as well as body deodorants and air fresheners and also cosmetic preparations. In the applications such as shower or bath soaps and gels, foam baths or shampoos, a neutral or even basic pH capable of inducing hydrolysis of the ester bond and thus release of a fragrant alcohol, may be reached for instance as the result of a high dilution of the base in water.
The compounds may also be employed in applications such as detergent compositions or cleaning materials for washing the dishes or various surfaces, whether intended for domestic or industrial use.
In these applications they may be used on their own, mixed together, or in mixtures with other perfuming ingredients, solvents or adjuvants currently used in perfumery. The nature and variety of these co-ingredients do not require a more detailed description here. In any case, this could not be exhaustive, as the person skilled in the art is able to select them on the basis of his or her general knowledge, and depending on the nature of the product to be perfumed and the required olfactory effect. These perfuming ingredients belong to classes of chemicals as varied as alcohols, aldehydes, ketones, esters, ethers, acetates, nitrites, terpene hydrocarbons, nitrogenous or sulphurous heterocyclic compounds, as well as essential oils of natural or synthetic origin. Many of these ingredients are moreover indexed in reference texts such as S. Arctander""s book, Perfume and Flavor Chemicals, 1969, Montclair, N.J., USA, or its more recent editions, or in other works of a similar nature.
The proportions in which the compounds according to the invention may be incorporated into the different products mentioned above vary within an extensive range of values. These values depend on the nature of the article or product to be perfumed and the required olfactory effect, as well as on the nature of the co-ingredients in a given composition when the compounds of the invention are used in mixtures with perfuming co-ingredients, solvents or adjuvants currently used in the art.
By way of example one may cite typical concentrations of the order of 0.1 to 5%, or more, by weight of these compounds relative to the weight of the composition in which they are incorporated. Concentrations below these may be used when these compounds are directly applied to the perfuming of the various consumer products mentioned above.
The invention will now be described in more detail in the following examples, in which the temperatures are given in degrees Celsius, the coupling constants (J) are given in Hertz and the abbreviations have the conventional meaning in the art.
Embodiments of the Invention